diff --git a/sympy/polys/polyfuncs.py b/sympy/polys/polyfuncs.py
index d69a292388..418a4f836b 100644
--- a/sympy/polys/polyfuncs.py
+++ b/sympy/polys/polyfuncs.py
@@ -246,6 +246,9 @@ def interpolate(data, x):
         else:
             Y = list(data)
 
+            if x == n:
+                return Y[-1]
+
             numert = Mul(*[(x - i) for i in range(1, n + 1)])
             denom = -factorial(n - 1) if n%2 == 0 else factorial(n - 1)
             coeffs = []
